The present invention is directed to a waste stripping tool which consists of a plain frame holding crossbars on which stripping equipments are secured. The tool is fitted in a machine for cutting sheets like items, such as, for instance, papers sheets or boards sheets.
A machine for cutting paper sheets or paper board sheets usually comprises successive stages, such as an infeed station in which the sheets are picked up one-by-one from a pile, a feeder table on which the sheet is aligned along its front and lateral edges before being seized by grippers which are on a continuous conveyor for the die cutting device. The grippers of the die cutting device carry the sheet through a cutting station, such as a platen press, having cutting and creasing tools, then to a stripping station in which waste portions of the die cut sheet are removed and, finally, to a delivery station where the cut sheets are collected.
Immediately after cutting, the sheet is carried into the flat-bed stripping station on a horizontal stripping plate provided with apertures which are aligned with the parts of the sheet which are to be stripped therefrom. Positioned above the horizontal stripping plate is a horizontal upper stripping tool holding device on which stripping pins or strippers and/or pressing items are mounted for movement in a vertical direction. Beneath the horizontal stripping plate, a second horizontal fixed stripping tool is arranged and holds a plurality of vertical telescopic pins which are aligned with the upper stripping pins for engaging portions extending into the apertures in the stripping plate.
The ends of these telescopic pins penetrate into the apertures of the stripping plate and reach a level which is slightly below the upper plane of the plate. Consequently, when the upper tool is lowered onto the cut strip, which is appropriately positioned, the coaction between the upper stripping elements and the telescopic pins will pinch the piece of paper or board which are to be stripped from the cut sheet in order to carry them down through the apertures in the stripping plate before dropping them into a basin or bin.
These stripping tools are repositioned with every change of the production run with a view to their being adapted to the new requirements, such as to type of sheet, size of the sheets, and the configuration of the parts to be stripped. Especially, the lower tools have to be constructed in such a way that its structure will not interfere with the free fall of the waste bits after their removal by the stripping tools.
To accomplish this, the tools ordinarily consist of a rectangular frame within which is fitted a grid of transverse members made of profile metal bars, preferably of aluminum. The bar's profile has a height that is greater than its width to insure a high rigidity in the vertical direction for the tool. The stripping equipment proper are then arranged, as required, along these transverse members and held in place by anchoring pieces or parts. In order to enable the user to create his own stripping tool for any configuration of paper sheets or board that are to be processed, these machines are supplied with an ample set of traverse members, i.e. an average of 40 pieces or members.
In practical use, the grid-shaped arrangement of crossbars or members changes in size due to the changes in size of the sheets of material being processed. This is particularly true with the lower tool frame which, for obtaining an easy stripping of the large-sized rear crosswise waste portion, should have no cross member after the one situated at the level for the knives separating the rear waste from the sheet. Thus, it has happened that the operators, in order to obtain shorter cross members or frame members to form a desired reduced size frame, cut several of the members to reduce their length. Due to this cutting, when longer members are necessary, new cross members must be purchased.